My brother has a young (<1) border collie. He's a very smart dog, but he's got a weird quirk that we'd like to correct if it's possible.

The dog is very good at letting us know when he needs to go outside, but he almost always does his business in two separate trips. We let him outside, he pees, he comes back inside, and like clockwork, he asks to be let outside again about five minutes later.

Has anyone ever experienced this before? Any ideas on how we might curb this behavior and teach him to take care of all his business at once?